Three-dimensional hetero-junction nanowire arrays have attracted considerable interests
due to their multi-functionalities and quantum effect as well as high surface to volume
ratio. Development of semiconductive hetero-junction nanomaterials through coupling
different semiconductive properties in the hetero-junction nanowires could significantly
improve the device performance by tuning/controlling the charge carrier generation,
recombination and/or transport across interface/junction. My research focus is to
explore three-dimensional hetero-junction nanowire array synthesis using different
synthesis methods, such as thermal evaporation, CVD, PLD, and wet chemistry methods
to study the controlled growth and charge transfer across the interface. The hetero-junction
nanowire arrays have been employed to fabricate different functional devices, such
as piezotronics and piezo-phototronics (Coupling piezoelectric and semiconductive
properties in core/shell nanomaterials), chemical sensors (mimicking olfactory receptor
array to fabricate "electronic nose"), solar cells (using enhanced charge separation
for type II solar cell integration), supercapacitors (engineering metal oxide NW arrays
by doping or shell coating to achieve higher supercapacitance), etc. Emerging green
materials, flexible materials, hybrid materials as well as their device fabrication
are also my interests.

High efficient perovskite solar cell integrated with nanomaterials

Organometallic halide perovskites (e.g., CH3NH3PbI3 and CH3NH3PbI3-xClx) have recently
emerged as a new class of light absorbers that have demonstrated a rapid progress
and impressive efficiencies (>15%) for solar conversion applications. These absorbers
have strong light absorption properties compared to other traditional thin film light
absorbers and can be produced by a low cost solution approach. The project is investigating
the synthesis of the pervoskites and integration of different nanostructures into
these new emerging solar cells, ultimately, to achieve higher efficiencies for commercial
applications.

As the resolution of electron microscope advanced into sub-Angstrom regime, the fine
nanostructures in terms to their properties can be resolved through advanced electron
microscopy. In this research, STEM, HRTEM, CBED, and EDS and EELS technique are applied
in functional nanomaterails study to reveal correlation between the nanostructure
and their unique properties to improve the synthesis routes, and ultimately to achieve
superior properties. The in-situ measurements and e-beam nanolithography are develpoed
for nanostructures and nanodevice fabrication, which is crucial to understand the
properties of nanomaterails and nanodevice physics.